Hypoxylon canker

Natural History
Hypoxylon canker on bark
Photo credit: G. Blakeslee - SFRC, Univ. of Forida

Hypoxylon canker is a disease caused by several different fungi in the genus Hypoxylon. It can attack hardwoods throughout Florida and can cause considerable damage by hastening the death of already weakened or stressed trees.

The fungus reproduces by means of small spores that are wind-borne, spreading from infected to healthy trees. The fungus invades the tree bark and, when the tree becomes severely weakened, the fungus invades the living tissues. As the tissues are infected, they die, eventually resulting in the death of the tree, or at least a major portion of the tree.


 

Identifying Characteristics

Identifying the disease: The major signs of hypoxylon canker are stem or branch dieback and patches of bark that fall off the tree. Wood surfaces beneath the displaced bark may be whitish-grayish in color due to the presence of the fungus and sometimes a black crust-like form of the fungus is also visible.
Susceptible trees: All hardwoods can be affected by hypoxylon canker but species of oak are the most highly susceptible. The fungus is more likely to infect oaks that have root system injuries or diseases or have been weakened or stressed by such factors as drought, poor nutrition, soil compaction, or construction damage.

 

Images

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Hypoxylon canker on water oak (Quercus nigra). Fruiting bodies of Hypoxylon stroma on oak. Symptoms of hypoxylon canker damage. Symptoms of hypoxylon canker damage.
Photo credit: Molly Giesbrecht
Texas A&M AgriLife Extension Service
Bugwood.org
Photo credit: USDA Forest Service
Region 8 - Southern Archive
USDA Forest Service
Bugwood.org
Photo credit: USDA Forest Service
North Central Research Station Archive
USDA Forest Service
Bugwood.org
Photo credit: USDA Forest Service
North Central Research Station Archive
USDA Forest Service
Bugwood.org

 

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